1. Field of the Invention
This invention relates generally to construction structures, and more particularly to an improved scaffold plank that interlocks with other similar planks to provide a continuous scaffold platform surface.
2. Description of the Related Art
A well known alternative to ladders is a horizontal platform constructed above the ground to permit workers, such as painters, masons and carpenters, to work on the exterior or interior walls of a building. Conventionally, scaffolds, or a system of scaffolds, are made of a frame of metal tubes, bars or other beam members to form a lattice on which a plurality of planks rest. A common frame is made, for example, of one and one-half inch outer diameter tubes. The frame provides the vertical support for the planks, and the planks provide the platform upon which the workers can perform their labor without being concerned about balancing on, and continually moving, ladders. The advantages of scaffolding systems are manifest.
Conventional scaffolds have many disadvantages, however. For example, in scaffolds made of wooden planks there is a danger of breakage due to the heterogeneity of wood, and the difficulty of identifying weak areas. Additionally, wooden planks are typically overlapped at ends where they rest on the scaffold frame, in order to prevent a plank from slipping off of a supporting frame member. However, this overlap of a board that is almost two inches thick provides a dangerous trip hazard for the careless worker.
Some problems associated with wooden planks have been addressed by the prior art. For example, it is well known to construct an aluminum plank having I-beam shaped rails extending longitudinally along opposite lateral edges of an aluminum panel. These planks have hooks at opposite ends to extend over the beams of a scaffold frame. Various articles for attaching to the end of a wooden plank for hooking over scaffold frames attempt to simulate, at less cost, these aluminum planks.
All of the attempts of the prior art, however, tend to have problems in one of two areas. First, the hooking systems for planks commonly create gaps between adjacent ends of planks, through which a worker could step, causing injury. Second, planks with hooks are only supported at the hooks, rather than across the entire plank width, thereby creating a stress concentration near the hooks that could cause a failure.
There is a need for a scaffold plank that avoids the problems of the prior art, yet is affordable and safe.
The invention is a scaffold plank. The plank has an elongated planar panel with first and second opposing major surfaces. The first major surface is the surface that can be walked on by workers or upon which materials, such as bricks, can rest. The second major surface is the underside of the plank.
There are preferably at least four elongated reinforcement ribs mounted to the second major surface, which is the underside of the plank. The ribs have opposing first and second lateral rib edges, and each rib is mounted at its first lateral rib edge to the second major surface of the planar panel. Preferably, the ribs are substantially parallel to, and equally spaced from, each next adjacent rib.
First and third notches are formed in a first end of the panel. These notches form part of an interlocking, finger-type joint that will be made between longitudinally adjacent planks. The first and third notches extend longitudinally into the panel and into first and third reinforcement ribs. Second and fourth notches are formed in a second, opposite end of the panel and provide the same function as the first and third notches. The second and fourth notches extend longitudinally toward the first and third notches into the panel and into the second and fourth reinforcement ribs. The notches define tabs, the tabs being the regions of the planar panel adjacent each notch, and the tabs of one plank will be inserted into the notches of a longitudinally adjacent plank, for forming the interlocking finger-type joint.
First and third transverse channels are formed in the first and third reinforcement ribs, respectively. Each channel is formed in the respective rib""s second lateral rib edge near the first end of the panel for forming a hook that will hook around a horizontal support member, such as a horizontal scaffold tube. Second and fourth transverse channels are formed in the second and fourth reinforcement ribs, respectively. Again, each channel is formed in the respective rib""s second lateral rib edge near the second end of the panel. With this channel arrangement, the horizontal frame members rest in the channels when the plank is in its operable position. The channels keep the plank from moving horizontally.